This invention relates to a method and apparatus for determining variation in the airway calibre of a respiratory system.
It is appropriate to monitor the respiratory system of asthmatics to assess the efficacy of treatment being carried out and to assess the likelihood of a life-threatening event.
Existing monitoring techniques include peak expiratory flow measurements employed by asthmatics in self-monitoring in the home, however, this technique requires the use of special breathing maneuvers which have to be learned by the subject.